1. Field of the Invention
The present invention relates to a structure of the flexing section of a multilayer flexible circuit board, which improves the flexibility of the flexing section of a multilayer flexible circuit board having a plurality of wiring conductors on which desired wiring patterns are formed with conductive foil.
2. Description of the Related Art
A conventional multilayer flexible circuit board which has a plurality of wiring conductors has a structure, wherein the respective wiring conductors including a flexing section are uniformly bonded with a flexible insulation base material using an adhesive agent. This unavoidably leads to deterioration in the flexing resistance of the flexing section. Depending on conditions, a few times of bending causes cracks in the wiring conductors, resulting in disconnection.
Such a problem is attributable to the distortion, particularly stretching and compressing, which occurs in the wiring conductors due to bending. Particularly in the case of a double-sided flexible circuit board, the flexing resistance deteriorates as the overall thickness of the circuit board increases because the wiring conductors are fixed with an adhesive agent.